Apparatus for coating articles

Abstract

Apparatus for applying a synthetic resin coating of predetermined thickness to various articles of different sizes and shapes from a relatively rapidly deteriorating solution of the resin in which an intermittently driven conveyor housed in a controlled atmosphere and suspending different article groups of like articles at spaced locations along the conveyor successively moves the articles from a loading station first to a cleaning station at which the articles are subjected to the action of an ultrasonic cleaner, then to a destaticizing station, then to a coating station at which a dip tank is rapidly raised to immerse the articles in the solution and is lowered at a controlled rate to provide a coating of the required thickness in a single operation, and finally through a precuring zone in which the coating dries tack-free to the loading station at which the coated precured articles can be removed. The coating solution is continuously circulated through the dip tank in such a way that the tank is always brim full and through a filter and chiller which maintains the solution below a predetermined temperature.

Having thus described my invention, what I claim is: 
     
       1. Apparatus for coating an article with a curable synthetic resin including in combination, a chamber, means in said chamber at a coating station for applying a coating of synthetic resin to an article, means for heating the ambient temperature in said chamber to a temperature sufficiently above room temperature to precure a coating of said resin applied to an article, a reservoir for holding a supply of said coating resin, means for feeding resin for said supply to said applying means, and means for cooling said supply of resin in said reservoir to a temperature below room temperature, said apparatus including a precuring zone in said chamber and a conveyor for carrying articles to said coating station and from said coating station through said precuring zone, cleaning means at a cleaning station, said conveyor successively carrying said article to said cleaning station and to said coating station and from said coating station through said precuring zone, said applying means comprising a tank, means mounting said tank below said conveyor and means for moving said article at said coating station and said tank relative to each other to immerse said article in said resin and to withdraw said article from said resin, said moving means performing one of said immersing and withdrawal operations at a relatively rapid rate and the other of said immersing and withdrawal operations at a relatively slower controlled rate, said, means for moving said article at said coating station and said tank relative to each other comprising means mounting said tank below said conveyor for movement from a first position remote from said conveyor to a second position adjacent to said conveyor, means for rapidly raising said tank from said first position to said second position to immerse articles supported by said conveyor at said cleaning station, and means for relatively slowly lowering said tank at a controlled rate from said second position toward said first position to withdraw said articles from said solution, said apparatus including means responsive to complete withdrawal of said articles from said tank for rapidly returning said tank to its first position. 
     
     
       2. Apparatus as in claim 1 in which said means for moving said article at said coating station and said tank relative to each other comprises a piston and a cylinder, said raising means comprising means for supplying fluid under pressure from a source to said cylinder, said lowering means comprising means for bleeding fluid from said cylinder, said means responsive to withdrawal comprising means for bypassing said bleeding means. 
     
     
       3. In a system for dip-coating articles of various lengths, apparatus including in combination, means for supporting an article to be coated at a coating station, a tank at said coating station for holding a supply of a coating solution, means mounting said tank at said coating station for relative movement of said tank and said article supporting means between a first position at which an article to be coated is immersed in said solution and a second position at which the longest article to be coated is completely withdrawn from said solution, means for relatively rapidly moving said tank and said supporting means relative to each other from said second position to said first position, means for initially relatively slowly moving said tank and said supporting means from said first position toward said second position to withdraw an article being coated from said tank to control the thickness of the coating applied to said article and means responsive to complete withdrawal from said tank of any article being coated prior to arrival of said tank at said second position for moving said tank rapidly back to said second position.